1. Field of the Invention
The invention concerns a razor blade unit for a safety razor, where a razor blade or two razor blades parallel to each other are embedded in a plastic part. The plastic part has a guide surface parallel to the cutting edges of the razor blades in front of the razor blades in the direction of shaving. It also has a top cap behind the razor blades in the direction of shaving. The razor blade unit is fitted with a device for reducing the friction of the plastic part when shaving.
2. Description of the Related Art
Known razor blade units for wet safety razors have a plastic part in which a razor blade or twin razor blade is embedded. In the case of the twin razor blade, two razor blades are embedded in the plastic part parallel to each other and with cutting edges offset from each other. The plastic part has a guide surface parallel to the cutting edges of the razor blades, in front of the razor blades in the direction of shaving. The plastic part of the known razor blade unit also has a top cap which is arranged behind the razor blades in the direction of shaving and covers the razor blades behind their cutting edges.
During the shaving process, the razor blade unit is moved over the skin. As this is done, pressure exerted on the safety razor by the user is transmitted to the skin by the surface of the razor blade unit. Even smaller razor blade units have further increased the specific pressure loads. Razor blade units made of plastic have the disadvantage of a high coefficient of friction greater than 0.3. Plastics, because of their polar nature tend to increase this coefficient of friction even further when wet. It is true that a shaving aid, for example foam or soap, reduces friction. However, studies have shown that the shaving process consists of micro-movements and in the first movement over a surface the shaving aid is pushed away so that all further movements are then made without any shaving aid.
One attempt to counter this disadvantage uses a piece of sponge, impregnated with water-soluble plastic, on the protective cap. This arrangement leaves behind a polymeric shaving aid on the skin. A disadvantage is that the effect of this shaving aid only occurs if the razor blade unit is frequently rinsed with water during the shaving process in order to dissolve the shaving aid out of the sponge. Another disadvantage is that sticky residues are left on the skin.